1. Field of the Invention
The present invention relates to a power supply unit.
2. Description of the Background Art
A large number of parts which generate heat such as a coil, a switch transistor, various diodes and the like are mounted to a power supply unit due to its circuit structure. In a casing, there exists a portion which is heated to a high temperature higher than 100xc2x0 C. for example.
Therefore, if an arithmetic circuit for calculating an output voltage value or output current value is to be mounted, since using maximum temperatures of a CPU or a digital IC which are constituent parts of the power supply unit are relatively low as low as about 85xc2x0 C., it is necessary to dispose the arithmetic circuit section sufficiently away from the heat-generating portions included in the power supply unit so that the power supply unit is not adversely affected by heat. For this reason, it is necessary to increase the casing in size, and the entire power supply unit is also adversely increased in size.
The present invention has been accomplished in view of such circumstances, and it is an object of the invention to provide a power supply unit in which parts having low using maximum temperatures are incorporated without increasing the entire power supply unit in size.
To achieve the above object, the present invention has the following structures.
A power supply unit of the present invention comprises a power supply circuit accommodating chamber and an arithmetic circuit accommodating chamber partitioned from each other by a partition wall, and a power supply circuit substrate and an arithmetic circuit substrate are accommodated in the power supply circuit accommodating chamber and the arithmetic circuit accommodating chamber, respectively.
Here, the accommodating chamber means a chamber capable of accommodating a substrate therein.
According to the present invention, since the partition wall functions as a heat insulation wall, it is possible to dispose and accommodate the arithmetic circuit substrate close to the power supply circuit substrate without receiving influence of heat from the power supply circuit.
In one embodiment of the present invention, at least one of a CPU, an amplifier, a digital IC and an indication LED is contained on the arithmetic circuit substrate.
According to the present invention, if the CPU, the amplifier, the digital IC or the indication LED having relatively low using maximum temperature is contained on the arithmetic circuit substrate, it is possible to incorporate such a part without increasing the power supply unit in size.
In another embodiment of the present invention, the power supply circuit substrate and the arithmetic circuit substrate respectively have connectors, and the connectors are connected to each other through an opening formed in the partition wall.
According to the present invention, it is possible to constitute a power supply unit having a desired additional function, for example, an indicating function or a communication function by connecting an arithmetic circuit of various specifications to one kind of power supply circuit. This is effective for reducing the costs in producing various kinds of power supply units.
In another embodiment of the present invention, the power supply unit further comprises a casing having the power supply circuit accommodating chamber, and an auxiliary case which is opened toward an outer wall of the casing.
According to the present invention, the outer wall of the casing itself functions as the partition wall for partitioning the power supply circuit accommodating chamber and the arithmetic circuit accommodating chamber from each other, the heat insulating structure can easily be formed only of necessary parts, and heat from the power supply circuit can effectively be insulated.
In a preferred embodiment of the present invention, the arithmetic circuit substrate calculates an output voltage value and an output current value of the power supply unit.
According to the present invention, calculated output voltage value or output current value can be indicated using the indicating LED contained on the arithmetic circuit substrate.